Том 52, № 3 (2018)

Preclinical studies demonstrate that a broad spectrum of human and animal malignant cells can be killed by oncolytic paramyxoviruses, which includes cells of ecto-, endo- and mesodermal origin. In clinical trials, significant reduction or even complete elimination of primary tumors and established metastases has been reported. Different routes of virus administration (intratumoral, intravenous, intradermal, intraperitoneal, or intrapleural) and single- vs. multiple-dose administration schemes have been explored. The reported side effects were grades 1 and 2, with the most common among them being mild fever. There are certain advantages in using paramyxoviruses as oncolytic agents compared to members of other virus families exist. Thanks to cytoplasmic replication, paramyxoviruses do not integrate the host genome or engage in recombination, which makes them safer and more attractive candidates for widely used therapeutic oncolysis than retroviruses or some DNA viruses. The list of oncolytic Paramyxoviridae members includes the attenuated measles virus, mumps virus, low pathogenic Newcastle disease, and Sendai viruses. Metastatic cancer cells frequently overexpress certain surface molecules that can serve as receptors for oncolytic paramyxoviruses. This promotes specific viral attachment to these malignant cells. Paramyxoviruses are capable of inducing efficient syncytium-mediated lysis of cancer cells and elicit strong immune stimulation, which dramatically enforces anticancer immune surveillance. In general, preclinical studies and phases I–III of clinical trials yield very encouraging results and warrant continued research of oncolytic paramyxoviruses as a particularly valuable addition to the existing panel of cancer-fighting approaches.

A critical analysis of proteomes provides a basis for understanding the operation of complex biochemical systems. A personalized approach to therapy takes into account biological uniqueness of each patient at genome, transcriptome, and proteome levels, and is a priority area in molecular medicine. The identification of proteoforms, which have dramatic impact on the phenotype of a disease, is a fundamental task of personal molecular profiling. Considerable progress of proteomic approaches presented new avenues for accurate, specific, and high-performance protein analysis. Thus, the identification of new efficient biomarkers can be expected based on studies of aberrant proteoforms associated with various diseases.

A dramatic increase in drug-resistant forms of tuberculosis (TB) stimulates a search for novel anti- TB drugs and studies of the drug resistance acquisition. One of the possible causes is a phenotypic resistance or drug tolerance which is not associated with genomic changes. The majority of anti-TB drugs eliminate 99% of MTB cells in 3–5 days, but the remaining subpopulation becomes unsusceptible to treatment and capable for long-term persistence with ability to resuscitate once the external adverse factor is removed. This evasion of the stress factor facilitates selection of resistant forms, thus warranting long-term treatment with at least four antibacterial drugs in TB. The review considers the main mechanisms of bacterial tolerance that are due to alterations in the cell wall, activation of efflux pumps, induction of transcriptional regulons, changes in metabolic flows, and modification of molecular machineries.

HIV-1 is one of the most variable viruses. The development of gene therapy technology using RNAi for AIDS/HIV-1 treatment is a potential alternative for traditional anti-retroviral therapy. Anti-HIV-1 siRNA should aim to exploit the most conserved viral targets. Using the deep sequencing of potential RNAi targets in 100-nt HIV-1 genome fragments from the clinical HIV-1 subtype A isolates in Russia, we found that the frequencies of all possible transversions and transitions in certain RNAi targets are 3–38 times lower than in adjacent sequences. Therefore, these targets are conserved. We propose the development of these RNAi targets for AIDS/HIV-1 treatment. Deep sequencing also enables the detection of the characteristic mutational bias of RT during the replication of viral RNA.

High metastatic ability and poor clinical outcome are the most known clinical features of the triple- negative breast tumors. Given that the tumor cells undergoing epithelial-mesenchymal transition (EMT) often gain malignant and invasive features, we have investigated the possibility of EMT reversal in triple-negative breast cancer cells by targeting the epigenetic-modifying enzymatic complexes named histone deacetylases (HDACs) and examined the possible mechanism underlying the HDACs-based inversion in model MDA-MB-231 cells. Cells were treated with a maximal tolerable 200 nM concentrations of classical HDACs inhibitor Trichostatin A (TSA) for 48 h and afterwards the invasiveness and immigration of the cells were evaluated in TransWell Invasion Scratch Wound Healing assays. Then, in treated and control cells, quantitative real time-PCRreacions were performed for assessing the gene expression of EMT biomarkers E-cadherin, Vimentin and transcriptional factor Slug. After TSA treatment, the invasion and migration properties MDAMB- 231 cells significantly decreased, gene expression of E-cadherin was significantly up-regulated, while the levels of Slug and Vimentin encoding mRNAs were suppressed. We conclude that inhibition of HDACs in triple- negative breast cancer cells may lead to inversion of EMT and the decrease of invasiveness by down-regulating the gene expression of Slug. Since EMT is known as a pre-metastatic process, triple-negative breast tumors, the EMT reversal effects of HDACs inhibition may reduce tumor cell metastasis.

Embryonic stem cells (ESCs) have the capacity for self-renewal and pluripotency. Due to high proliferative activity, ESCs use a specific pathway of the formation of ATP molecules, which can lead to the development of the adaptive metabolic response under the conditions of energy deficiency (which is different from the response of differentiated cells). It is known that metabolic signals are integrated with the cell cycle progression; however, the signaling pathways that connect the availability of nutrients with the regulation of cell cycle in ESCs are insufficiently studied. We have studied the effect of the AICAR agent, which imitates an increase in AMP level and induces the activation of the metabolic sensor AMPK, on proliferation, cell cycle distribution, and pluripotency of mouse ESCs (mESCs). It has been demonstrated that cells treated with AICAR do not stop at the control G1/S point of the cell cycle, since they do not accumulate P21/WAF1 (G1/S checkpoint regulator), despite P53 activation. On the contrary, AICAR increases the rate of mESC proliferation, which correlates with increased expression of pluripotency marker genes (OCT3/4, NANOG, SOX2, KLF4, ESRRB, PRDM14). In addition, an increase in the transcription of the HIF1α gene (a key regulator of the cell proliferation and viability, as well as glucose metabolism under stress) was detected. An increase in the expression of glycolytic enzyme genes (LDHA, ALDOA, PCK2, GLUT4) under the effect of AICAR indicates a change in mESC metabolism towards increased glycolysis. Thus, AICAR-dependent AMPK activation as one of possible mechanisms of the mESC adaptive response to the emergence of energetic imbalance is not accompanied by a cell cycle arrest at the G1/S checkpoint, but involves the processes of increasing glycolytic activity.

Pituitary tumor-transforming gene-1 (PTTG1) encodes securin, a multifunctional protein involved in development of various types of cancer. Securin participates in the regulation of sister chromatids separation and the expression of multiple genes involved in the control of the cell cycle, metabolism, and angiogenesis. In several human cell lines, we have found a novel short isoform of securin mRNA, which does not contain exons 3 and 4. After the translation of this new mRNA, a shortened protein is produced that, like the full-size form, is able to activate the transcription of cyclin D3 gene (CCND3), which controls the G1/S transition and angiogenesis factors VEGFA (vascular endothelial growth factor), and FGF2 (fibroblast growth factor 2) in HEK293 cells. However, unlike the full-size protein, the short isoform of PTTG1 does not affect the MYC gene expression because it lacks the DNA-binding domain, which is needed for its interactions with the MYC promoter. Furthermore, the short form of securin does not influence the expression of MYC transcriptional targets, such as TP53 and IL-8. Thus, we found a novel isoform of securin which is able to activate a more restricted repertoire of genes compared to the full-size protein.

The possibility of enhancing the immunogenicity of the rabies virus glycoprotein antigen encoded by a DNA vaccine has been investigated. Ubiquitin-like protein FAT10 has been attached to the N-terminus of the glycoprotein to target it to the proteasome and stimulate its presentation by MHC class I. Two forms of the protein, chimeric and original, have been detected in cells transfected with the DNA construct encoding the chimeric protein. The presence of the glycoprotein on the cell surface has been detected by immunostaining of transfected cells. The production of IgG and IgG2a antibodies has been more efficiently induced in mice immunized with the plasmid that encodes the chimeric protein than in those immunized with the plasmid that encodes unmodified glycoprotein. Moreover, the level of IgG2a antibodies exceeded the level of IgG1 antibodies, which indicates a preferential increase in the Th1 component of the immune response. The proposed DNA construct that encodes a modified glycoprotein with a proteasome degradation signal may be a promising DNA vaccine immunogen for post-exposure prophylaxis of rabies.

Identifying amino acid positions that determine the specific interaction of proteins with small molecule ligands, is required for search of pharmaceutical targets, drug design, and solution of other biotechnology problems. We studied applicability of an original method SPrOS (specificity projection on sequence) developed to recognize functionally significant positions in amino acid sequences. The method allows residues specific to functional subgroups to be determined within the protein family based on their local surroundings in amino acid sequences. The efficiency of the method has been estimated on the protein kinase family. The residues associated with the protein specificity to inhibitors have been predicted. The results have been verified using 3D structures of protein–ligand complexes. Three small molecule inhibitors have been tested. Residues predicted with SPrOS either in contacted the inhibitor or influenced the conformation of the ligand–binding area. Excluding close homologues from the studied set makes it possible to decrease the number of difficult to interpret positions. The expediency of this procedure was determined by the relationship between an inhibitory spectrum and phylogenic partition. Thus, the method efficiency has been confirmed by matching the prediction results with the protein 3D structures.